1. Field of Invention
The present invention relates generally to an electronic device with an embedded system therein, and more particularly to an embedded device and method for secure firmware update in embedded system.
2. Related Prior Art
Many commercial systems and consumer products rely on embedded systems to perform their functions. Embedded systems often take the form of general purpose microprocessors or microcontrollers to carry out specialized functions by firmware, such as an embedded operating system stored in a nonvolatile memory. In many cases, the firmware may be updated to fix defects or to introduce new features. However, such updates carry a risk—if for some reason, such as power outage, download failure or incomplete download, both the original and the new version embedded operating systems can work no more, which causes the embedded system to cease to operate properly. Typically, such a failure is difficult to correct because the embedded system ceases communicating.
Taiwan Patent No. 1229818 discloses an apparatus and a method for keyboard controller firmware update. In order to allow secure update without computer system shutdown or the operating system software ruined, the system works on several programs simultaneously—the so-called “Multi-Tasking”—the executing kernel of the computer, the processor, jumps from task to task to update firmware.
Additionally, Taiwan Patent No. 1227898 discloses an apparatus and a method for CD-ROM drive firmware update. In order to avoid the processor from ceasing to operate, the value of the program counter of the CD-ROM drive is reset once the update process is complete.
The abovementioned prior arts are intended to secure update through different techniques. However, there are still some uncontrollable conditions, such as power outage, that these existing update methods do not adequately insure against the risk of failure, and therefore are not suitable for embedded systems.